appendVisitorIDsTo (Cross-Domain Tracking)

This function lets you share a visitor's Experience Cloud ID across domains when browsers block third-party cookies. To use this function, you must have implemented the ID service and own the source and destination domains. Available in VisitorAPI.js version 1.7.0 or higher.

Track Visitors Across Domains When Browsers Block Third-Party Cookies

ID service writes a first- and third-party cookie to the browser when a person visit your site (see Cookies and the Experience Cloud ID Service ). The first-party cookie contains the MID, a unique ID for that visitor. The third-party cookie contains another ID used by the ID service to generate the MID. When a browser blocks this third-party cookie, the ID service cannot:

  • Regenerate the unique ID for that site visitor when they navigate to another domain.
  • Track visitors across different domains owned by your organization.

To help solve this problem, implement Visitor.appendVisitorIDsTo(url). This property lets the ID service track site visitors across multiple domains even when their browsers block third-party cookies. It works like this:

  • As a visitor browses to your other domains, the Visitor.appendVisitorIDsTo(url) appends the MID as a query parameter in the URL redirect from the original domain to the destination domain.
  • The ID service code on the destination domain extracts the MID from the URL instead of sending a request to Adobe for that visitor's ID. This request includes the third-party cookie ID, which is not available in this case.
  • The ID service code on the destination page uses the passed-in MID to track the visitor.

See the code sample for details.

Append Visitor ID Code Sample

The following example can help you get started with Visitor.appendVisitorIDsTo(url). When implemented properly, your JavaScript code could look similar to the following example.

//Code on Domain A
var destinationURL = "www.destination.com";

//Call the ID service
var visitor = Visitor.getInstance(...);

//Append visitor IDs to the destination URL
var destinationURLWithVisitorIDs = visitor.appendVisitorIDsTo(destinationURL);
     //Result of appendVisitorIDsTo includes destination URL, Experience Cloud ID (MCMID), and Analytics ID (MCAID)
     "www.destination.com?adobe_mc=MCMID=1234|MCAID=5678"

//Redirect to the destination

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